Sussin



Dec. 19 1950 D. susslN 2,534,637

X-RAY ILLUMINATING MECHANISM Dec. 19EE 1950 D. susslN 2,534,637

x-RAY ILLUMINATING huzcfmmsm Dec. 19, 1950 D. sus'sm 2534,63?7

X-RAY ILLUMINATING MECHANISM Filed March 26, 1945 5 Sheets-Sheet 3 ATTO R N EYS Dec. E9, 1950 D. susslN X-RAY ILLUMINATING MECHANISM 5 Sheets-Sheet 4 Filed March 26, `1945 MEW ATTOR N EYS Dec. l, 1950 D. susslN 2,534,537

X-RAY ILLUMINATING MECHANISM Filed March 26, 1945 5 Sheets-Sheet 5 Patented Dec.. 19, 1950 UNITED STATES PATENT OFFICE .1K-RAY. ILLUMINATING MECHANISM David Sussin, Southflort Mitchell, Ky., assignor to The'Kelley-Koett Manufacturing Company, Sovington, Ky., Aa corporation oi @hic `fippiication March 26, 1945, SerialNo. 584,920

6 Claims. l

This invention relates to X-ray apparatus and more particularly to apparatus for use in viewing X-ray films.

One of the principal `objects of the invention is to provide apparatus for viewing rX-ray lms ofvarying densities under conditions of illuminationcontrolled to accord with the density of the lrnand to permit illumination,sufliciently intense for accurate appraisal of factors .contained in iilm, having all or portions thereof of densities outside the lighting capacity .of previous illuminators.

`Still another object-of theinvention is to provide apparatus for viewing X-ray films which isprovided with means for effecting varying illuminations up to very high intensity illuminationymuch'higher than heretofore usedor considered practicable-while maintaining the surface of the illuminatedsection sufficiently cool to prevent any objectionable effect upon the-nlm.

Another object of the invention is to provide apparatus for viewing X-ray lms in which two sources of Aillumination are provided, one of which comprises a large illuminated lm receiving surface, with means .for variable intensity of illumination over a wide range and up to much higher illumination .than heretofore available to permit of taking, viewing, and appraising higher density lms, andthe other of which provides for illuminating a selected small area oi the film under very high intensity illumination coordinated with very high ydensity of such area; and with suitable means for maintaining the illuminated surfaces under all intensities of illumination suiiiciently cool to prevent objectionable or adverse effect uponthe lm.

Othei` objects and advantages of the invention will be Vapparent from thedescription and claims and the drawing.

In the drawing, in which a preferred embodiment ofthe invention is illustrated, Vand in which like characters ofreference designate like parts throughout the several views thereof:

Fig. l is a front elevational view of apparatus embodying the invention, illustrated for Viewing X-ray film;

2 is aside elevational View of the apparatus of Fig. l, looking from the right-with inside parts dotted in to show general location thereof;

Fig. 3 is a rear elevational view of the apparatus of Fig. l, with inside parts dotted in to show general location thereof;

lil

Fig. 4 is a section Vvon the line fL-li of looking inthe vdirection of the arrows;

Fig. 5.is.a fragmentarysectional. vieu.7 through one .corneroftheapparatus showing details of construction;

Figli isaside elevation similar to Fig. 2 1but with the side plate removed and come .parts shown: in dotted lines ,and certain details omitted, the .directionof .the .View belngindieated by lthe line 6 6 in Fig. l;

Fig. '7v is Vafragmentary detail showing the detachablemeans for latching or holding the interconnection of the light reecting chamber vand the water cell;

Fig. 8 is a sectional view, along the lined-il of Fig l looking in the direction of the arrows, of the inside of the apparatus showing the spotlight and water cell in section;

Fig. 9 isl a wiring diagram; and

Figi() is a detail in cross sectionoi the mountingrof the right hand endof the viewing plate.

In most lcasesthe viewing of X-ray films for the detection of llaws vin the object radiographed has been limited bythe amount of light avaiiable for .illuminating the film while it is vbeing studied and appraised. Frequently the iight source has beeninadequate to permito `proper and necessary illumination vof the iilm, with the result that accurate appraisal of many of the factors is difficult or impossible, and even with the result that vital information actuaiiy on the lm cannot be seen because of lack of intensity of light to illuminate the iilm properly. -As Ya result'radiographers -from theil` general experience have learned to make or deveiop films in densities readable on existing equipment, even thougha longer exposure might supply y additional iniormationconcerning the internal structure :being photographed. These densities in practicearemeasured in terms of the v/'eilirnown H & D scale. This has beenparticularly true in :industrial radiography, as in the examination `of industrial devices, such as, castings or welds,.-for possible .flaws which are ofsuch a nature thatarhighdegree of contrast is'requiredto show-theirpresence. Also, because of` dierences in cross-section, shape and. form, etc., .-azcasting orthe likemay be such thatzwlien the image-oi certain portions of thedevice are oi a photographic density on Nthe .nlm 1p1-oper for :satisfac- -.tory Viewing with .ordinary illuminators other portions of the Yimage willsbeof a densityibeyond the range thatcanbe viewed by that iiluininator.

It hasfbeena generalpracticeto limit the YeX- Fig. l

posure so that the greatest magnitude of lm density has been 1.5 on the H & D scale. This is a scale evolved for guidance in radiography. Photographic density on the H 8: D scale refers to the logarithm of the reciprocal of the transmission of light through the photographic image. Thus if the photographic image transmits 116 of the light incident on it, it has a density of unity as indicated by the formula 1 Density =10g [im] That is Density=log =log 10=1 In the same way if the photographic image transmits M00 of the incident light 1 Dens1tylog-l/10O--log 100-2 Other values in this H & D scale are similarly determined. When such heretofore appraisable maximum density of 1.5 produces a iilm in which some of the thicker parts of the X-rayed object may be adequately observed with former illuminators, other thinner parts would be of such density as to be beyond proper viewing and appraisal under the maximum lighting of such illuminators.

When two adjacent portions of an object produce only a small difference in the absorption of the X-ray beam, the resultant image in the radiograph will have only slight diierences in density for the two adjacent regions. The ability of the observer to distinguish such small differences in density increases as the total density of the image on the film is increased provided there is suicient illumination of the denser films, or film portions. With sufficient illumination of the Whole of such a denser ilm, or any denser parts or adjacent portions thereof. The observer is thus able adequately to distinguish and appraise in the image on the film regions of the object which as heretofore exposed and illuminated have had an unobservable or unappreciable small difference in absorption of the X-ray beam or have been so dense as to be beyond the power of the illuminator and therefore not successfully observable or appreciable.

With the use of this invention exposures may be used which produce lm densities far in excess of those heretofore used as a maximum properly viewable, that is, intensity of illumination as much as four times that available heretofore in illuminators may be applied to the whole lilm, or sixteen times as much to small areas of the iilm. In the construction as shown, with the light bulbs close to the lm and the reflectors used, the intensity of illumination over the whole lm is substantially 1600 candle power and substantially 6400 candle power over the smaller spot illuminator for a limited area of the lm (tested by a photometer). As a result the present invention will provide a sufficiently wide range of intensity of illumination so that whole films o1' sections thereof may be readily viewed, studied and appraised, which were beyond the lighting capacity of former illuminators, and in the present invention this may be accomplished by varying the maximum intensity of the source of light of the illuminator While adequately preventing any increase in heat energy from injuring the viewing mechanism or the films.

By the use of longer exposures and greater amounts of X-radiation incident on any object or any part thereof images of ilavvs such as referred to above may be caused to have the desired contrast with images of the surrounding portion of the article, and by the use of adequate illumination greatly increased contrasts may be readily viewed and appraised which would not even be visible with the ordinary illuminating device.

In cases where it is necessary to radiograph an object of variable thickness the resulting lm will be a combination of light and heavy densities depending on the amount of X-ray absorption at given points. The present invention permits of using such exposure as will give the required maximum density and of viewing the varying densities with maximum efficiency, in that this invention provides means for variably controlling the density of illumination to accord with the density of the film being viewed, and to give such illumination as will permit of studying and appraising the iilm under the most desirable conditions, either as to portions of lighter density or portions of heavier density; and the invention therefore makes it possible to study properly the lm and appraise an object, Whether requiring a small amount or a large amount of X-ray radiation and Whether the film requires a high or low light intensity.

A preferred embodiment of apparatus of this invention is illustrated, and with this apparatus a wide range of intensity of illumination has been found satisfactorily usable, and yet in spite of the large amount of illumination provided, the illuminated surfaces are maintained sufficiently cool, even when operated continuously, so that lms will not curl or buckle and may be viewed sequentially without damage to the illuminating device and without damage to the lms.

The apparatus comprises a box or casing designated generally by the numeral IS and having a. top with louvers 35-35, a back with a removable panel l i which is held in position by suitable iastenings li and which covers an opening of suicient extent to permit the operator to mount and dismount the light xtures, two removable sides |39, a base and a front the greater portion of which is occupied by a glass viewing plate I5. An opening is provided in the front of the box to receive this viewing plate. As shown this viewing plate l5 is satisfactorily translucent to visible light emanations, very satisfactory results in operation being attained when the plate l5 is substantially 14 by 17 inches, the usual size of lm used in radiography and is of opal glass, or glass opalized on one side. With such size plate the whole of a usual size 14 by 17 inch lm may be viewed at one time.

Within the box and directed toward the plate l5 is a reflector l2 in which are mounted a pair of electric bulbs I6, light from which is thrown by the reflector, upon the plate. The means by which the reiiector and the plate are mounted in the box is shown in Figs. 5 and 10, of which Fig. 5 is a detailed cross section through the left hand front corner of the box as seen in Fig. l, and Fig. l0 is a detailed cross section through the mounting of the right hand end of the glass plate l5, the showing in each figure being illustrative of a convenient and satisfactory construction which may be economically manufactured and assembled, or disassembled when access to the interior of the mechanism is desired or required for repair, etc. Looking now at Fig. 5 the illustrative construction is shown as comprising a side wall |30 of the box, bent at right angles to form a front flange I3I to the inside of which is attached by welding or the like a vertical spacer and support |36 which is angle shaped, one side of the angle serving for attachment to the flange I3| and the other serving as a support for the reflector. Outside the corner formed by the flange I3| there is xed an angle shaped member |32 which may be chromium-plated or otherwise decorated and which adds appearance and strength to the corner of the box. This corner brace or angular strip is attached to the side wall |30 by screws |33, and which for simplicity of disclosure are omitted from Figs. l, 3 and 8; and this strip may be readily attached or detached and the side walls |30 applied for assembly or removed for access to the interior of the box I and the mechanism therein.

As seen at Figs. 1 and 10 metal plate |31 extends from the top to the bottom of the box and is suitably cut away as indicated at 83 in a mannery to be hereinafter more fully disclosed. Mounted vertically on the edge of plate |31 is a strip |38 which is held in place by screws |39. Attached to the inside of the metal plate |31 adjacent the left-hand edge thereof as viewed in Fig. l is an angle support |40 similar in its construction and method of attachment to angle support |36. The reflector I2 has diverging top and bottom parts 25-26 and parallel sides 21-28. Across and below the bottom of the left-hand opening in the box and extending the full extent thereof is an angle shaped member 3| which serves as a support for the glass plate.

The sides 27 and 28 of the reflector |2 are extended forwardly as indicated at 21' and 28 and the outer ends are offset in order to remove the attaching screws |30 from the line of light and prevent the throwing of shadows on the viewing plate I5. The ends of these extended sides are bent over to form flanges |35 and 28" which with the cooperating parts I3| and |38 respectively form grooves to hold the edges of the plate I in position, the bottom of the plate resting on the supporting flange 3|. When the device is being assembled the plate I5 is not emplaced until the reflector I 2 has been put in position. The size of this reflector is such in its over-all dimensions that it can be placed in the box through the front opening before the strips I3I and |38 have been mounted. The reflector having been placed inside the box itis attached to the uprights |00 and |36 by screws |34 and assumes the position shown in Fig. 4.

At the forward ends of the parts 25 and 25 of the reflector there is mounted a heat baille 30 which may conveniently be glass of a type which permits visible light to pass and intercepts heat and heat radiations. This glass is mounted between spring clips 32 which are attached to the members 25 and 26 and hold it resiliently against rotating or movement in use and transportation of the device, the weight of this glass plate is supported primarily upon metal plates 312 affixed, as by Welding, to the side walls 21, 28 of the reilectors. At their rear ends the top and bottom parts of the reflector are flattened out as shown at 25-26 to receive a channel shaped mounting or support 2| for the light bulbs I6I6, these substantially parallel portions 25-26 having enough springiness or flexibility to hold the support 2| firmly when pushed into position between them. The lights, their sockets, a light diffuser plate and supports therefor are carried as a unit on the support 2| which is frictionally held by the resilience of the members 2526'. This mounting is pushed into place from the rear through the elongated opening, in the back of the casing, when the covering plate I l is removed and it may be as readily pulled out for replacing bulbs I6, etc.

Positioned back of plate 30 are the two electric bulbs designated I6 which are mounted in a double socket member I8, which in turn is supported in a cylindrical holder shown as a T-section of pipe I9, this in turn having threaded into it a pipe nipple 20, the other end of which extends through an opening in the support 2| to which it is fastened by inside and outside lock nuts both designated by the numeral 22.

The support 2| carries two clamp members or projections EEO-50'. These members, as shown for example in Fig. 4, are united and held between the portion 2| and the inner lock nut 22 and extend forwardly to receive between their front ends a diffuser plate 62 which is interposed between the light bulbs and the plate 30 and tends to diffuse light from the bulbs so that concentrated light does not impinge directly upon the plate 30 and viewing plate I5 but light rays from very high intensity spots of light emanation are intercepted and broken up or diffused so that more uniformity of intensity of illumination will be effective upon the glass plate I5. By means of such diffuser and the reflecting inclined and side walls which house the lamps I6-I6 the maximum intensity of diffused light will be thrown upon the opal glass plate, and by means of the voltage regulator 56-51 (Figure 1), the intensity of the illumination from the bulbs lil-I6 can be increased or decreased to meet the varying conditions of lm density being viewed. It is thought unnecessary to describe the internal construction of the voltage regulator 56, as a suitable variable voltage auto transformer, such for example as that commonly known in the trade as Variac, is available and well understood.

The light bulbs shown and preferably used are of the photo flood type each providing 250 watts of illumination, are positioned closely adjacent the viewing plate, and as the interior of the reflector is painted with a paint having a very high reflecting factor, the visible light rays may be directed against the opal viewing plate I5 to provide a substantially uniform intensity of illumination, over the whole of a 14 by 17 inch film, which is approximately four to five times that heretofore used in viewing such X-ray illms; and with such films will give adequate illumination so that they may be adequately and substantially uniformly illuminated and viewed and appraised at densities heretofore non-usable.

It should be borne in mind that seemingly small variations on the H & D scale represent quite large variations in illumination required. For example, adding 1.0 to the H & D scale density requires ten times as much illumination. And the 1600 candle power referred to above is satisfactory for ordinary lm contrasts substantially up to 3.8 on the H & D scale, whereas an increase in density to approximately 4.4 can adequately be viewed only with the spot illuminator of approximately the 6400 candle power above referred to. The nature of the object radiographed affects contrast in density which may affect the intensity of illumination required; but, generally, the densities referred to may be adequately appraised under the intensities of illumination stated. In,

fact, the gures given are conservative; for example, .densities of 4.5 have been satisfactorily viewed and appraised with the 640() candle power spot illuminator.

Reflector I2 and the support 2| are suitably paintedto withstand the temperatures to which subjected, and the inner surfaces exposed to emanations from the closely adjacent light bulbs Iare painted with a suitable heat resistant and highly. reflective white paint. Asa result of this, substantially all of the light. emitted by the bulbs IE5, I ortat least such a greatly preponderant part thereof as to give in practice substantially uniform lightinfr of the plate I5, is transmitted directly and by reflection toward the opal glass viewing plate I5 to provide high intensity illumination thereof .per unit area.

As shown, theheat absorbing plate 3G is spaced a short distance, about an inch being usually foundsuicient, back of the opal glass plate, thus providing a space extending from the bottom of the housing, and to the left of the dividing partition 3l, as shown in Figs. 3, 4 and 8, through which cooling air may be forced, passing from the bottom up, as shown in Fig. 4, and then out through'the louvers 35 which are formed in the top of the casing.

Beneath the bottom 2Eof the reflector is an angular partition .3l theextreme front'of which extends baclr from the front wall and the rear portion of which is angularly bent so as to be diagonally placed as shown in Fig. 8 and which increases in height from the front to rear since it conforms to the shape of the bottom of the reflector. A narrow baffle 'l'I is placed above the top of the fan housing 42 and extends from the rear portion of the member 3l to .the right side wall of the casing and serves to assist in directing the aiiowfrom the fan 5G so that the air will be blown eifectively over the small area-very high illumination part of the illuminating mechanism positioned in the space at the right of the large illuminator chamber behind the viewing plate I5. There are two high speed air circulating fans dii-GB shown, one for each side of the casing and furnishing air to the light chambers onthe left andright sides of the chamber respectively. Both fans are alike in construction and operation. For example, the fan 4B, as shown in Figs. 3 and ll, is `of approximately an 8 inch size and is rated for continuous operation so that whenever the lamps It, IG are illuminated, a sufficient current of air will be blown in through the housing 42, with which the fan 5 is associated, across the bottom of the reflector portion 2B, up through the'space between the plates I5 ,and 3B at such a rate that sufficient heat energy will be absorbed from the heat absorbing' plate 3B and also from the inside of the illuminated viewing plate I5 so that the tempera- .ture of both plates will be kept low enough to avoid any damage or injury to the apparatus and in addition the temperature of the plate E5 will be kept suciently low so vthat X-ray film may be placed and held Vfirmly against that plate I5 without becoming unduly heated and without resultant damage.

The heat absorbing glass may be of character as known on the market for absorbing non-luminous radiant energy, while at the same time absorbing only a small percentage of the visible light rays. A glass of this sort can be obtained which will absorb sufficient of the non-visible radiation impinging upon it to prevent an objectionable quantity of heat energy passing therethrough to adversely affect the illuminated viewing screen or plate or the X-ray lm thereagainst while permitting passage of a large preponderant part .of the luminous waves which impinge upon it. .Of course, glasses of various kinds may be used for the plate 38 which will vary somewhat as to their transparency tovisible radiation and to non-visible radiation, and in the efficiency .of transmission of visible light to impinge upon .the opal glass while absorbing or reflecting back into the light enough of the heat energy emanating and reflecting means resulting from emanations from the light source so that most of the heat energy can be dissipated by the current of air forced between the two glass plates by the fan 40 and the amounts of radiant energy so removed or dissipated and the amount of visible light impinging on the viewing screen will determine the relativeeniciency of the apparatus as to permissible intensity of the illumination per inch area onthe plate l But it has been found that either opal glass or glass which has been opalized on one side can be used for the plate I5, and when a quality of glass which is adequately heat absorbing but light transparent glass is used for the plate 30, the resultant coordination of parts in the mechanism and heat energy removal therefrom will readily permit of securing sufficient intensity from two 250 watt photo flood lamps to permit of adequately illuminating and accurately viewing and diagnosing X-ray lm having densities as high as not less than about 3.8 on the H 8: D scale.

The voltage regulator or control 56, which is shown in dotted lines in Figs. l, 2 and 6 has an operating handle 5? outside the box I0, by means of which the setting of the current control may be varied so that the light emitted by bulbs I6 may be varied by stepless adjustments, as desired. Very satisfactory results have been secured with the apparatus illustrated and the with the voltage control so constructed as to give a desired range of voltage variation from O to the maximum voltage utilized for the operation of the illuminator in this invention. As shown diagrammatically in Fig. 2 a dial portion 58 for this voltage regulator is marked on the outside of the casing, a range of from 60 to 130 volts, and this range will ordinarily befound satisfactory to meet the usual operating conditions. This voltage regulator is positioned in the compartment space I3, to the right of the partition 3l, as viewed from the front.

The fan @Gis positioned or mounted adjacent to an opening c2 in the back of the illuminator casing, and is so constructed that, in the apparatus as shown, it will cause a circulation of approximately 900 cubic feet of air per minute across the bottom of the compartment I2, up between the glass plates iti-3U, and out through the louvres or exhaust openings 35. This amount of circulating air is sufficient to prevent undue heating of the opal glass plate I5 when cach of the bulbs IS-lS-is a No. l photo-flood lamp of 250 watts, as described. The fan 40 is similar in mounting construction and function. Also each of the fan openings is shown covered by a wire mesh screen to protect against accidental injury to the operator and prevent ingress of objectionable objects or materials which might injure the fans or other parts of the mechanism. These screens are indicated by the cross-lined portions shown at the bottom of each fan opening.

Preferably the casing is provided adjacent the upper edge of the glass plate I5 with a plurality of spring members 48, each having a roller 49, which A9 are so arranged that they will exert sufficient spring pressure against the upper end of the glass plate to permit of inserting the upper end of the film beneath these rollers and to hold it suspended so that the iilm may be held flat against the glass I while it is being viewed.

In the right hand portion of the casing l0, as viewed from the front, another photo flood lamp 10 is mounted in a suitable socket 1| which is mounted at the rear of the reflecting chamber 12, in the nature of a spotlight; the inner surface of' this reflecting chamber being treated to be highly reflective of visible emanations from the bulb 10. Suitable results, and a very high degree of reective capacity, have been attained by applying a highly reflective silver surface to all the inner walls of this reilecting chamber 12 so that substantially all the light is directed forwardly toward the plate B3, thus giving a very high conconcentration of light over a small area. reilecting chamber is provided with a plurality of radiating fins 13, for dissipating heat received, during operation, from the bulb. Also, this reecting chamber, with the lamp carried therein,

is constructed to be supported from a water cell, i

the light for high intensity illumination on the plate 83.

As shown, the water cell 14 comprises a horizontally arranged cylinder having an expansion chamber 14 of the Sylphon type to compensate for expansion and contraction of the iluid in the e:

water cell under varying temperatures during operation. The water cell has a plurality of heat dissipating fins 00, over which the air from the fan sweeps to affect cooling of the water, in the cell, which is absorptive of the non-visible heat rays and transparent to the visible rays, and may thus be effectively cooled in operation. The cylinder 14 carries at its front end a ange 8|, and at its rear end a somewhat similar ilange member 02, which however, as shown, is of larger diameter than the flange 8|. The front end of the Water cell 14 is circular. Against the circular front end of the water cell rests a circular gasket 04. Against the circular gasket 84 is a plate 83 as of plastic which is unaffected by the uid in the cell and the intense light which illuminates it. A plate of methyl methacrylate such as the material well known as Plexiglas is satisfactory in use. Against the transparent plate 83 is a metal plate 85 having spring arms 81-88 bent slightly backward and having slots 92-93 respectively at the ends of the upper and lower arms or extensions 81-88 respectively. As shown the upper slot is arranged vertically and the lower slot 93 substantially horizontally. Bolts 0S pass through the plate 85 and the llange 8| and hold the parts in sealing relation, and suirlciently to support the water cell and light assembly. 'I'he member 85 has an opening as large as the interior of the cell. Screw threaded studs .B0-0|, which are welded to the front wall of the casing I0, are adapted to engage in slots 92. and 93 when arms 81 and 80 are slid under nuts 04-05 on said screws, and said nuts may be tightened to hold said arms in place. By this arrangement of the slots, as described, the supporting plate may be readily removed by loosening the nut S5 and giving a small angular swing to the plate member, and the entire plate and water cell and light assembly thus readily removed or replaced through the opening covered by the plate The rear end of the water cell Z4 supports a sleeve ||0 having a rear flange H5, and a front ange |0| which latter has threaded openings therein to receive the adjusting screws or bolts |00, which are positioned through openings in the ilange |0| and the flange 02 at the rear end of the water cell. The rear end of the water cell is likewise sealed in watertight relation, by means of a glass plate |02, which is held between a gasket of rubber or the like |03 on the cell, and a similar gasket |03 against the cooperating face of the flange |0I. Tightening of the screws or bolts |00 will then pull flange |0| toward the end of the water cell to clamp the glass plate |02 tightly in position between the gaskets, to give a water tight connection. This flange 0| is pre1'- erably circular and is provided with a circular opening which overlies the periphery of the glass plate |02, and the gaskets |03' and tightening of the bolts |00 will pull the flanges |0| and 82 together against the respective cooperating gaskets |03--i03 and the glass plate |02 is thus sealed tight against the rear end of the water cell and the sleeve is fastened to the rear end of the water cell. However, since the plate |02 is of glass and exposed directly to the heat generated by the bulb 10, it is of heat resistant glass as described above in connection with plate 30.

The sleeve l I0 has an inside diameter which is approximately the same or very slightly smaller than the outside diameter of the slotted front end of the lamp chamber 12, and is adapted to receive and hold the front end of the lamp chamber 12 in operative position. The flange 5 has a latch member |24 (Figs. 6 and '7) formed of a metal strap odset or bent about midway so that when one part is attached, as by spot welding, to the flange I5 the other part is spaced therefrom to provide a latch space into which the locking lug or catch |25 on the lamp supporting cham'- ber 12 may be readily moved into position therein to hold the parts in assembled relation. The cylindrical chamber is projected into the sleeve I0 and a part turn will then bring the catch |25 under the latch member |24.

The fan 40 is mounted to the right of the bale 31, as seen from the front, in the back wall of the box and within a cylindrical housing 42' corresponding to housing 42 about fan 40. When this highly concentrated, or spotlight, lportion is being used the fan 40 is simultaneously energized and its draft is directed over the water cell and spotlight assembly, flowing over the fins 13 of the light rellector, and the fins 30 of the water cell and over the expansion chamber and out through the louvers 35'. In this way the heat from the bulb and that absorbed by the Water is adequately dissipated and the nlm is protected even against the very intense light and heat rays emitted by the bulb 10.

The detachable strip |38, as shown in Fig. 10, when bolted in position, and having one edge overlying the large plate l5 to hold it in assembled relation, has the other edge portions overlying but spaced from the overturned flange of member |40. This overturned llange and the cooperating edge of the strip |38 receive between them a metal panel |31, which closes the front of the space in which the water cell 11| and associated parts above described are positioned, this panel |31 being preferably of sheet metal properly enameled, to correspond with the remainder of the sheet metal utilized in forming the parts of alltimes provided by the foot switch l52, and no operation is possible exceptwhenithe plug lei has been insertedi'n operative position.

' While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be mede therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. An illuminator for viewing X-ray lms and the like, comprising a housing, a light transmittingviewing plate at one side of said housing against which an X-ray film may be viewed, a highintensity source of visible light located in said housing behind said viewing plate, said high intensity source of light being surrounded by an enclosure having its inner surfaces highly reflective of radiation from light source and positioned to direct said radiations in a small diameter beam toward said viewing plate, cooling ns surrounding said light enclosure, a water cell comprising a metallic cylinder having cooling ns upon the exterior thereof, a closure for the rear end of' said water cellwhich istransparent to visible light rays but substantially opaque to nonvisible light rays, said viewing plate being attached as a `closure for the front of said water cell,

means for detachably connecting said water cell and said viewing plate to the front of the housing, means carried by the opposite end of said water cell for receiving and supporting the enclosure for said source of high intensity light, and means for controlling the effective lm area illuminated by said light source and for preventing uncontrolled diffused lighting of said film areas.

2. An illuminator for viewing X-ray films and the like, comprising a housing, a light transmitting viewing plate at one side of said housing against which an Iii-ray film may be Viewed, viewing a high. intensity source of visible light located in said housing behind said viewing plate, said high intensity source of light being surrounded by an enclosure having its inner surfaces highly reective of radiation from said light source and positioned to direct said radiations in a small diameter beam. toward said viewing plate, cooling fins surrounding said light enclosure, a water cell comprising a inetaliic cylinder having cooling fins upon the exterior thereof, a closure for the rear end of said water cell which is transparent to visible light rays but substantially opaque to nonvisible light rays, said viewing plate being attached as a closure for the front of said water cell, means for connecting said water cell and said viewing plate to the front cf the housing, means carried by the opposite end of said water cell for receiving and supporting the enclosure for said source of high intensity light, and means for flowing cooling fluid over said water cell and light enclosure at a rate sufficient to remove heat energy therefrom to maintain the temperature thereof and of said viewing plate sufficiently low to avoid deleterious effects to the mechanism and also to the X-ray lrn.

3. An illuminator for viewing X-ray films and the like, comprising a housing, a light transmitting and diffusing viewing plate at one side of said housing against which an X-ray lm may be viewed, a high intensity source of visible light located in said housing behind said viewing plate, said high intensity source of light being surrounded by an enclosure having its inner surfaces highly reflective of radiation from said light 14 source and positioned to direct said radiations-in` a small diameter beam toward-said viewing plate; cooling fins surrounding said light enclosure, a water cell comprising a metallic cylinderhaving cooling ns upon the exterior thereof,` a closure for the rear end of said water cell which istransparent to visible light rays but substantially opaque to non-visible light rays, s aidviewing` plate being attached to a closure for the front of said water cell, means for detachably connecting said water cell and said viewing plate to the front of the housing, and means carried by the opposite end of said watervcell for receiving and supporting the enclosure for said source of high intensity light, the intensity of said source of high intensity. light and the means for effecting con-1 centration of visible light emanations therefrom upon said viewing plate being coordinated to give'fsuch illumination of a small area of'X-ray` film held against said viewing plate as will permit viewing and appraising areas of film of den'- sities on the H & D scale which are substantially above 3.8 on the H & D scale in density.

An illuminator for viewing X-ray films and the like, comprising a housing, a light transmitting and diffusing viewing platefat one side of said housing against which an X-ray lm may be viewed. a high intensity sourceof visible light located in said housing behind said viewing'plate, said high intensity source of light being'surrounded by an enclosure having its-inner surfaces highly reflective of radiation from said light source and positioned to direct said radiations in a small diameter beam toward said viewing plate1 cooling fins surrounding said light enclosure, a water cell comprising a metallic cylinder having cooling fins upon the exterior thereof, a closure for the rear end of said water cell which is transparent to visible light rays but substantially opaque to non-visible light rays, said viewing plate being attached as a closure for the front of said water cell, means for connecting said water cell and said viewing plate to the front of the housing, means carried by the opposite end of said water cell for receiving and supporting the enclosure for said source of high intensity light, the intensity of said source of high intensity light and the means for effecting concentration of visible light emanations therefrom upon said viewing plate being coordinated to give illumination intensity up to 6400 candle power against said viewing plate. means for flowing cooling fluid over said water cell and light enclosure at a rate sufficient to remove heat energy therefrom to maintain the temperature thereof and of said viewing plate suinciently low to avoid deleterious effects to the mechanism and also to the X-ray filmh and means for varying the area of film to be viewed and constructed to prevent uncontrolled diffused light from being effective on the film areas.

5. In an illuminator for viewing X-ray films and the like including a casing adapted to receive a source of light and having a viewing aperture in one side thereof provided with a light transmitting and diffusing viewing plate against which an X-ray nlm may be viewed, means providing a second viewing aperture in said casing substantiallv smaller than said first named aperture, a housing adapted to support a high intensity source of light and having inner surfaces highly reflective of light from a source mounted therein, a high intensity source of light within said housing, said housing being positioned within said casing to direct light from a source mounted therein in a small diameter beam towards said small viewing aperture, said housing being provided externally with cooling fins, a Water cell comprising a metallic cylinder having cooling fins upon the exterior thereof, light transmitting closure members for the rear and front ends of said Water cell, means for detachably mounting said water cell Within said casing with said front closure member substantially coinciding with said small viewing aperture, means carried by the rear end of said water cell for supporting said housing, and means for flowing cooling fluid over said water cell and housing to carry oi heat therefrom.

6. An illuminator for viewing X-ray lms and the like including a casing provided with a small viewing aperature in one side thereof against which an X-ray film may be Viewed, a housing adapted to support a high intensity source of light and having inner surfaces highly reflective of light from a source mounted therein, a water cell comprising a metallic cylinder having cooling flns upon the exterior thereof, light transmitting closure members for the front and rear ends of said water cell, means for mounting said Water cell Within said casing with said front closure member substantially coinciding with said small viewing apparatus, a source of high intensity light Within said housing means carried by the rear end of said Water cell for supporting said housing in position to direct light from said source mounted therein in a small diameter beam t- 16 wards said small viewing aperture, means for energizing said light source, and mea-ns coupled with said energizing means for directing W of air over said water cell and housing to carry off heat therefrom when said named light source is energized.

DAVID SUSSIN.

CITED The ioliowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 768,827 Stewart Aug. 30, 1904 1,000,231 Bowles Aug. 8, 1911 1,203,387 Scheckerling Dec. 12, 1916 1,500,867 Glover July 8, 1924 1,576,557 Strully Mar. 16, 1926 1,797,322 Callender Mar. 24, 1931 1,846,538 'Ihompson Feb. 23, 1932 1,891,498 Borden Dec. 20, 1932 1,988,654 Haag Jan. 22, 1935 1,989,803 Hoben Feb. 5, 1935 2,012,940 Buck Sept. 3, 1935 2,038,784 Ghadiali Apr. 28, 1936 2,079,373 Jordan May 4, 1937 2,188,294 Ganoung Jan. 23, 1940 2,242,525 Kirlin May 20, 1941 2,279,084 Tillyer Apr. 7, 1942 Certificate of Correction Patent No. 2,534,637 December 19, 1950 DAVID SUSSIN It is hereby certiiied that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column ll, line 50, for the Word larger read higher; column 13, lines 41 and 42, strike out viewing, column 14, line 9, for to a read as a.; column 15, line 28, after housing insert a comme; column 16, line 3, after directing insert L 5 and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oiice.

Signed and sealed this 3rd day of April, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents. 

